Which exam assesses this module?

These topics are part of Unit 2 Body Systems, Genetics, Microorganisms and Health, a written paper worth 40 percent of the GCSE. Foundation tier lasts 1 hour 30 minutes and Higher tier lasts 1 hour 45 minutes. Expect structured and longer questions, including a process such as natural selection or genetic engineering.

What is the difference between natural selection and selective breeding?

Both make useful alleles more common over generations, but the selecting agent differs. In natural selection the environment decides which organisms survive and reproduce. In selective breeding humans choose which organisms breed. Genetic engineering is different again, directly transferring a single gene into an organism rather than breeding over generations.

What ethical issues come up in this module?

Genetic engineering and cloning raise concerns about long-term effects on health and the environment, modified genes spreading to wild plants, reduced biodiversity, and the ethics of cloning animals. CCEA expects balanced answers that weigh clear benefits, such as insulin and higher crop yields, against these genuine uncertainties.

How should I revise this module?

Learn the variation types and graphs, then the ordered steps of natural selection (variation, competition, survival, reproduction, change) and apply them to antibiotic resistance. Memorise the four menstrual-cycle hormones and their roles, the selective-breeding cycle, and the steps of genetic engineering. Practise CCEA past-paper extended answers and ethical discussions.

Northern IrelandBiology

CCEA GCSE Biology: Variation, reproduction and applied genetics overview

Q: What does the variation, reproduction and applied genetics module cover?

This module covers Unit 2 sections 2.5 to 2.7: continuous and discontinuous variation and its causes, natural selection and evolution with the fossil and antibiotic-resistance evidence, the reproductive system and the hormones of the menstrual cycle, selective breeding, and genetic engineering and cloning.

An overview of the variation, reproduction and applied genetics module of CCEA GCSE Biology (Unit 2 sections 2.5 to 2.7), mapping variation, natural selection and evolution, the reproductive system and hormones, selective breeding, and genetic engineering and cloning, and how they are examined.

Generated by Claude Opus 4.87 min readCCEA 6568 Unit 2.5 to 2.7Updated 2026-06-14

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What this module covers
How it is examined
How to study it

This module is about where differences come from and how humans use genetics. It covers Unit 2 sections 2.5 to 2.7 and is examined on the Unit 2 written paper. This page maps the topics and links to a focused answer page for each.

What this module covers

Variation: Continuous and discontinuous variation, the genetic and environmental causes, how data is presented, and the role of mutation. Start with Variation.
Natural selection and evolution: The theory of natural selection, antibiotic resistance, and the fossil evidence. See Natural selection and evolution.
The reproductive system and hormones: The reproductive systems, the menstrual cycle hormones, and the use of hormones in contraception and fertility treatment. See The reproductive system and hormones.
Selective breeding: How parents with desired features are chosen over generations, examples, and the benefits and risks. See Selective breeding.
Genetic engineering and cloning: How genes are transferred between organisms, examples such as insulin and GM crops, cloning, and the ethical issues. See Genetic engineering and cloning.

How it is examined

These topics appear on Unit 2, worth 40% of the GCSE. Expect structured questions on variation types and graphs, the steps of natural selection, the menstrual-cycle hormones, the selective-breeding cycle, and the genetic-engineering process, plus a longer answer or a balanced discussion of ethical issues.

How to study it

Learn the variation types and graphs, then the ordered steps of natural selection and apply them to antibiotic resistance and the peppered moth. Memorise the four menstrual-cycle hormones and their roles, the selective-breeding cycle, and the genetic-engineering steps with the enzymes and vector. Practise CCEA extended answers and ethical discussions, then finish with the module quiz.

Sources & how we know this

CCEA GCSE Biology specification — CCEA (2017)